AIDS (acquired immuno-deficiency syndrome) is a disease caused by an infection of one of retroviruses, human acquired immuno-deficiency virus (HIV). Any effective therapeutic method for treatment of the infection of the human acquired immuno-deficiency virus has not yet been developed, and the spread of AIDS has become a worldwide serious problem. Azidodeoxythymidine (AZT), dideoxyinosine (DDI), and dideoxycytosine (DDC) have been developed to date as anti-retroviral drugs having inhibitory activities against reverse transcriptions by retroviruses, which are used for the therapeutic treatment of AIDS. However, these drugs induce severe side effects such as cytotoxicities and their clinical applications are limited.
In addition, appearances of resistant strains having resistances against these drugs have also been problems. Therefore, developments of medicament having potent anti-retroviral activity and reduced side effects are much desired.
An object of the present invention is thus to provide novel substances which have excellent inhibitory activities against retroviruses and are useful as anti-retroviral drug with reduced side effects such as cytotoxicity.